THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



CONDUCTED BY 



SIR DAVID BREWSTER, K.H. LL.D. F.R.S.L. & E. &c. 

 RICHARD TAYLOR, F.L.S. G.S. Astr. S. Nat. H. Mosc. &c. 

 SIR ROBERT KANE, M.D. M.R.I.A. 

 WILLIAM FRANCIS, Ph.D. F.L.S. F.R.A.S. F.C.S. 

 JOHN TYNDALL, Ph.D. F.R.S. &c. 



" Nee aranearum sane textus ideo melior quia ex se fila gignunt, nee noster 

 vilior quia ex alienis libamus ut apes." Just. Lips. PoUt. lib. i. cap. 1 . Not. 



VOL. X.— FOURTH SERIES. 

 JULY— DECEMBER, 1855. 



LONDON. 



TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET, 

 Printers and Publishers to the University of London : 



SOl.U BY LONGMAN, BKOWN, GREEN, AND LONGMANS; SIMPKIN, MARSHALL 

 AND CO.; WIIITTAKEIl AND CO.; AND PIPEU AND CO., LONDON : 



BY ADAM AND CHARLES BLACK, AND THOMAS CLARK, 



EDINBURGH; SMITH AND SON, GLASGOW; HODGES 



AND SMITH, Dublin; and putnam, 



NrW YORK. 



